/*******************************************************************************
 * Copyright (c) 2011 MadRobot.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the GNU Lesser Public License v2.1
 * which accompanies this distribution, and is available at
 * http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
 * 
 * Contributors:
 *  Elton Kent - initial API and implementation
 ******************************************************************************/
package com.madrobot.json;

import java.io.IOException;
import java.io.Reader;
import java.io.StringReader;
import java.io.Writer;
import java.util.List;
import java.util.Map;

/**
 */
public class JSONValue {
	/**
	 * Parse JSON text into java object from the input source.
	 * Please use parseWithException() if you don't want to ignore the
	 * exception.
	 * 
	 * @see com.madrobot.json.JSONParser#parse(Reader)
	 * @see #parseWithException(Reader)
	 * 
	 * @param in
	 * @return Instance of the following:
	 *         org.json.simple.JSONObject,
	 *         org.json.simple.JSONArray,
	 *         java.lang.String,
	 *         java.lang.Number,
	 *         java.lang.Boolean,
	 *         null
	 * 
	 */
	public static Object parse(Reader in) {
		try{
			JSONParser parser = new JSONParser();
			return parser.parse(in);
		} catch(Exception e){
			return null;
		}
	}

	public static Object parse(String s) {
		StringReader in = new StringReader(s);
		return parse(in);
	}

	/**
	 * Parse JSON text into java object from the input source.
	 * 
	 * @see com.madrobot.json.JSONParser
	 * 
	 * @param in
	 * @return Instance of the following:
	 *         org.json.simple.JSONObject,
	 *         org.json.simple.JSONArray,
	 *         java.lang.String,
	 *         java.lang.Number,
	 *         java.lang.Boolean,
	 *         null
	 * 
	 * @throws IOException
	 * @throws JSONParseException
	 */
	public static Object parseWithException(Reader in) throws IOException, JSONParseException {
		JSONParser parser = new JSONParser();
		return parser.parse(in);
	}

	public static Object parseWithException(String s) throws JSONParseException {
		JSONParser parser = new JSONParser();
		return parser.parse(s);
	}

	/**
	 * Encode an object into JSON text and write it to out.
	 * <p>
	 * If this object is a Map or a List, and it's also a JSONStreamAware or a
	 * JSONAware, JSONStreamAware or JSONAware will be considered firstly.
	 * <p>
	 * DO NOT call this method from writeJSONString(Writer) of a class that
	 * implements both JSONStreamAware and (Map or List) with "this" as the
	 * first parameter, use JSONObject.writeJSONString(Map, Writer) or
	 * JSONArray.writeJSONString(List, Writer) instead.
	 * 
	 * @see com.madrobot.json.JSONObject#writeJSONString(Map, Writer)
	 * @see com.madrobot.json.JSONArray#writeJSONString(List, Writer)
	 * 
	 * @param value
	 * @param writer
	 */
	public static void writeJSONString(Object value, Writer out) throws IOException {
		if(value == null){
			out.write("null");
			return;
		}

		if(value instanceof String){
			out.write('\"');
			out.write(escape((String) value));
			out.write('\"');
			return;
		}

		if(value instanceof Double){
			if(((Double) value).isInfinite() || ((Double) value).isNaN())
				out.write("null");
			else
				out.write(value.toString());
			return;
		}

		if(value instanceof Float){
			if(((Float) value).isInfinite() || ((Float) value).isNaN())
				out.write("null");
			else
				out.write(value.toString());
			return;
		}

		if(value instanceof Number){
			out.write(value.toString());
			return;
		}

		if(value instanceof Boolean){
			out.write(value.toString());
			return;
		}

		if((value instanceof JSONStreamAware)){
			((JSONStreamAware) value).writeJSONString(out);
			return;
		}

		if((value instanceof JSONAware)){
			out.write(((JSONAware) value).toJSONString());
			return;
		}

		if(value instanceof Map){
			JSONObject.writeJSONString((Map) value, out);
			return;
		}

		if(value instanceof List){
			JSONArray.writeJSONString((List) value, out);
			return;
		}

		out.write(value.toString());
	}

	/**
	 * Convert an object to JSON text.
	 * <p>
	 * If this object is a Map or a List, and it's also a JSONAware, JSONAware
	 * will be considered firstly.
	 * <p>
	 * DO NOT call this method from toJSONString() of a class that implements
	 * both JSONAware and Map or List with "this" as the parameter, use
	 * JSONObject.toJSONString(Map) or JSONArray.toJSONString(List) instead.
	 * 
	 * @see com.madrobot.json.JSONObject#toJSONString(Map)
	 * @see com.madrobot.json.JSONArray#toJSONString(List)
	 * 
	 * @param value
	 * @return JSON text, or "null" if value is null or it's an NaN or an INF
	 *         number.
	 */
	public static String toJSONString(Object value) {
		if(value == null)
			return "null";

		if(value instanceof String)
			return "\"" + escape((String) value) + "\"";

		if(value instanceof Double){
			if(((Double) value).isInfinite() || ((Double) value).isNaN())
				return "null";
			else
				return value.toString();
		}

		if(value instanceof Float){
			if(((Float) value).isInfinite() || ((Float) value).isNaN())
				return "null";
			else
				return value.toString();
		}

		if(value instanceof Number)
			return value.toString();

		if(value instanceof Boolean)
			return value.toString();

		if((value instanceof JSONAware))
			return ((JSONAware) value).toJSONString();

		if(value instanceof Map)
			return JSONObject.toJSONString((Map) value);

		if(value instanceof List)
			return JSONArray.toJSONString((List) value);

		return value.toString();
	}

	/**
	 * Escape quotes, \, /, \r, \n, \b, \f, \t and other control characters
	 * (U+0000 through U+001F).
	 * 
	 * @param s
	 * @return
	 */
	public static String escape(String s) {
		if(s == null)
			return null;
		StringBuffer sb = new StringBuffer();
		escape(s, sb);
		return sb.toString();
	}

	/**
	 * @param s
	 *            - Must not be null.
	 * @param sb
	 */
	static void escape(String s, StringBuffer sb) {
		for(int i = 0; i < s.length(); i++){
			char ch = s.charAt(i);
			switch(ch) {
				case '"':
					sb.append("\\\"");
					break;
				case '\\':
					sb.append("\\\\");
					break;
				case '\b':
					sb.append("\\b");
					break;
				case '\f':
					sb.append("\\f");
					break;
				case '\n':
					sb.append("\\n");
					break;
				case '\r':
					sb.append("\\r");
					break;
				case '\t':
					sb.append("\\t");
					break;
				case '/':
					sb.append("\\/");
					break;
				default:
					// Reference: http://www.unicode.org/versions/Unicode5.1.0/
					if((ch >= '\u0000' && ch <= '\u001F') || (ch >= '\u007F' && ch <= '\u009F')
							|| (ch >= '\u2000' && ch <= '\u20FF')){
						String ss = Integer.toHexString(ch);
						sb.append("\\u");
						for(int k = 0; k < 4 - ss.length(); k++){
							sb.append('0');
						}
						sb.append(ss.toUpperCase());
					} else{
						sb.append(ch);
					}
			}
		}// for
	}

}
